and time-independence is obtained by setting \(\gamma _k=k\,t\) . We recall that
static potentials are obtained from non-propagating modes in quantum field
theory [1]}, [2]}, [3]}.
If we write the classical potential as
\(V_{\rm RN}=\int \limits _0^\infty \frac{k^2\,{\mathrm {d}}k}{2\,\pi ^2}\,\left[\tilde{V}_M(k)+\tilde{V}_Q(k)\right]j_0(k\,r)\ ,\) 
